I will admit that I am jealous of artists who can depict sources of light credibly in their artwork. I am not talking about the sun, although this is challenging too, but mechanical forms of light. Light strips, dial illumination, or screens are examples of what I am talking about. Strong sources of light in situations where there are lots of reflections and/or atmospheric effects. I remember many Michael Whelan paintings where the light source had a well-defined shape and yet still depicted the softness associated with the glow most light sources have.
I still work hard to achieve such effects in my paintings. The easiest way of creating a bright light source is to take a light color and surround it with a very dark source. But what do you do when you have a strong enough artificial light source to still be seen in a daylight situation? I haven’t tried that yet, but I have been amazed by artists that can pull off such complex lighting.
I will share one trick that I have learned from using Gimp 2.8. In my painting “Juliette and Josephus” the diffuse halo of light around the sun was achieved by painting the light color of the sun on a transparent layer above all the layers and then using the smudge tool to thin the color. If you looked at the layer with a white background, you would hardly see anything. However, if you put it against a very dark background like I did, you see a soft wash of bright color or a halo around the more solid image of the sun. The contrast brings out the light color. I hope to further explore using light washes on layers over different backgrounds after seeing how well this worked.